The case, stringing and fretting design of the 1543 Venetian clavichord by Dominicus Pisaurensis

an article published in  De Clavicordio, Proceedings of the V International Clavichord Symposium/Atti del V congresso internazionale sul clavicordo.  Magnano, 5-5 September 2001, edited by Bernard Brauchli, Alberto Galazzo and Ivan Moody, (Musica antica a Magnano, Magnano, 2002), 91-107

by Grant O'Brien



The stringing materials

            The graph shown in Figure 4 in the previous chapter plots the corrected string scalings produced by moving the bridges by the distances suggested in the analysis above.  As before thin lines have been drawn on the graph corresponding to the critical string lengths and the scalings for the iron, yellow brass and red brass stringing materials suggested by Table 4.  In the treble, moving the top bridge 2.7 mm towards the frets has had the effect of making the treble scalings in the top octave almost perfectly Pythagorean.  Below c2 the string scalings foreshorten gradually until the scaling curve crosses over the line for Pythagorean yellow brass scalings between the played notes fT and g.  At this point it would be possible to string the rest of the notes on this bridge with yellow brass strings.  The top notes on the middle bridge exceed or equal the critical string length given by the note tenor c and would have to be strung with iron strings otherwise breakages would occur.  The lowest two notes on the middle bridge and the top three notes on the bottom bridge could all be strung using yellow brass.  The bottom three strings on the bottom bridge corresponding to the notes of the short octave could all be strung in red brass.


            These three stringing materials are indicated by grey (iron), yellow (yellow brass) and red (red brass) in the design length column in Table 6 and by the points indicating the individual measurements in Figure 4.  In Figure 4 the faint lines giving Pythagorean scalings for c2 =  8, 6 and 5 Venetian once represent, in effect, the limits of each of the stringing materials.  Between the lines for  8 and 6 Venetian once, for example, stringing in iron is possible, but yellow brass strings would break.  Between the lines for 6 and 5 Venetian once, stringing with iron would be possible, but it would also be possible in yellow brass.  In this region yellow brass, being more flexible[1] than iron, would sound better.  Similarly stringing in red brass for the notes to left of the faint line for c2 Pythagorean scalings based on  5 Venetian once would result in the best tonal quality there.


The re-entrant iron stringing for the three unfretted notes c, cT and d is unusual, and is a direct consequence of using separated bridges rather than a single continuous bridge as is more normal.


Figure 4 – Theoretical scalings with all of the bridges moved slightly from their present positions

Dominicus Pisaurensis clavichord, Venice, 1543

Leipzig Musikinstrumentenmuseum der Universität, Clavichorde Cat. No. 1


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[1] That it, it has a lower stiffness or Young’s modulus.  The lower the stiffness of any string, the more the partial overtones resemble a perfect harmonic series.  This is generally recognised subjectively by Western ears as a more musically pleasing sound quality.